C to Crouch Script

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local Animate
local Humanoid = player.Character:FindFirstChild('Humanoid')

mouse.KeyDown:Connect(function(Key)
 if Key == "c" then
  local Animation = Instance.new("Animation", player.Character)
  Animation.AnimationId = "rbxassetid://YourID"
  Animate = Humanoid:LoadAnimation(Animation)
  Animate:Play()
 end
end)

mouse.KeyUp:Connect(function(Key)
 if Key == "c" then
  Animate:Stop()
 end
end)